Composition and process of manufacture



PATENT OFFICE.

UNITED STATES JOHIT I. CAVANAG-H, OF III-BEEN, CONNECTICUT, ASSIGNOB TO CONNECTICUT TELEPHONE & ELECTRIC COMPANY, INCOBTOB-ATED, OF MEBIDEN, CONNECTI- CUT, A CORPORATION OF CONNECTICUT.

GOIEPOSITION AND PROCESS OF MNUFACTUBE.

No Drawing.

To all whom it may concern:

Be it known that I, JOHN F. CAVANAGH, a citizen of the United States of America, residing at Meriden, Connecticut, have invented a new and useful Composition and Process of Manufacture, of which the following is a specification.

My invention relates particularly to a composition which can be molded intovarious articles while in a cold state, that is, the ordinaryv atmospheric temperature. The composition is particularly intended for the manufacture of certain electrical fittings and parts but obviously may be used for other purposes.

The main objects are to provide a composition which is inexpensive, which'will keep without deterioration for a considerable time before molding, which is easy to handle and which molds well. As above stated, it is desired that the composition can be molded at ordinary atmospheric temperature. It is also desired that the finished product shall have considerable mechanical strength, that it will not alter its shape in process of manufacture, is not readily inflammable, is a good non-conductor of electricity, of low absorptive character, will take a good finish and is of permanent character, that is, practically unaffected by atmospheric conditions and ordinary conditions of use.

The preferred ingredients are asbestos, linseed oil and asphalt in the approximate proportions as follows Ingredients. i is gg fi Example.

Asbestos 78 to 87 83% Linseed oil 13 to 7 10% Asphalt 9to 6 7% asphalt are first placed in a kettle and the temperature raised to about 400 F. These are preferably stirred to insure an intimate mixture. The asbestos fiber is placed in a mixing machine and the hot fluid oil and Specification of Letters Patent.

Patented July 13, 1920.

Applieation filed larch 7, 19l9. Serial No. 231,192.

asphalt mixture is then added. The mixing machine is immediately started and allowed to run for about an hour without the addition of any extra heat. The mixture of course becomes cooler and takes on the form and consistency and general appearance of brown sugar. Heat is then applied to the mixing machine and the temperature gradually raised during a period of about two hours more until a temperature of 400 F. is reached. This temperature is then maintained, the machine running all the time .for about two hours more when the finished composition should generally resemble black gun powder in appearance. It is then allowed to cool and is ready for the molds.

It is desirable to thoroughly mix the ingred-ients before adding heat other than that retained by the fluid composition. Otherwise the mixture is liable to be irregular, that is, it may resolve itself into lumps and light fluffy powder. The same bad effect is produced by raising the temperature of the mixture too rapidly. On the other hand if the mixing operation is allowed to proceed without heat, the mixture is likely after 8 to 10 hours to separate into pellets about the size of peas. The surface of these pellets is likely to become glazed while the inside is tacky. In this condition the material does not adapt itself readily to any of the ordinary means of pulverizing. It is desirable therefore that the relationship of heat to mechanical agitation be such as to prevent the material from lumping into pellets without being so intense or sudden as to produce an over-cure of the small detached particlesof the mixture. This composition is advantageously mixed in the presence of the air so that the oxidizing action is enhanced and a deep color produced.

Although I have stated above the desirable proportions of the ingredients for carrying out my invention, 1 do not wish to be limited precisely to them. It will be obvious that a certain percentage of other inert materials may be substituted for a part of the asbestos, although I do not consider it desirable. If a greater percentage of oil is incorporated a longer time is necessary to bring the mixture to a moldable state as it tends to get doughy, while on the other hand process or finished article.

when in proper proportions it tends to re- I tacky to permit of rapid manipulation in molding. On the other hand a reduction in the proportion of oil decreases the strength of the finished article and makes it less susceptible to a fine finish. A reduction in the proportion of asphalt seems to permit the oil to oxidize more rapidly with the result that the keeping qualities of the mass in moldable condition are impaired.

While it is possible that a small part of the linseed oil and a small part of the asphalt may be replaced with other ingredients, I do not know at the present time of any substitutes which will improve the sider however, that small substitutions of other ingredients such as china wood oil for part of the linseedoil or colophony for part of the asphalt would avoid my claims provided the general advantages herein set forth are attained. The oil should be an oxidizing oil the drying of which is controlled by an asphaltic ingredient.

The matter of uniformity of the mixture I consider of great importance. In the compositions heretoit'ore known on the market for cold molding, much depends upon the use of a volatile solvent for a binder. The proportions of this solvent require constant adjustment to compensate for evaporation with the result that the mixture as delivered to the mold does not run uniformly. By my process and with my composition, the desirable characteristics are retained almost indefinitely. As a result the molding action is uniform at all times-.thus producing a uniform productjf whether the dies are filled by measure orby weight. On account of the fact that practically no evaporation takes place it is possible to'measure the composition by volume when filling the molds. This saves a great deal of time and increases thellout-put of a molding machine mater1a y.

The composition is molded under high pressure into the desired shape, either with or without metallic inserts. The articles are then taken to an oven where the temperature is gradually raised to about 400 F. or 420 F. during a period of about five hours and then kept at this temperature for about two hours when they are finished.

The finished article is of a homogeneous character, quite hard and capable of being highly polished. The color varies with the proportions of the ingredients and-the heat treatment, and when carried as above indicated may be made a very dark brown or almost black. The articles are also capable of being machined. and cut or drilled.

Although it is preferable to apply heat during the mixing of the other ingredients with the asbestos, it is possible to obtain fairly good results with some proportions of ingredients by mixing them for a period of say two hours, then removing the mixture from the mixing machine and spreading it out in drying pans exposed to the air for a long period of say two weeks. At the end of this time it should then be again placed v time. I do not con I claim 1. The composition in fine granular form suitable for molding at atmospheric temperature and under pressure which includes approximately from 78% ,to 87% of inert material, from 7% to 13% of a drying oil,

and from 6% to 9% of an asphaltic substance for controlling the drying of the oil.

2. A composition in fine granular form and adapted for cold molding and comprising a finely divided mixture of an inert substance about 83%, a drying oil about 10%,

and an asphaltic substance about 7%.

3. The process of forming a molding composition comprising, heating linseed oil. and asphalt to melt the asphalt and insure a good mixture, adding the mixture to asbestos fiber and mixing the ingredients as they cool, then raising the temperature gradually while mixing and maintaining a heated condition until the mixture has the characteristics of a finely divided powder.

4. The process of forming a molding composition which includes mixing from 7 to 13% of a drying oil and 6 to 9% of an as phaltic substance while hot with 78 to 87% of an inert base and allowing the mixture to cool as the mixing continues until as it cools it assumes about the consistency of brown sugar, then reheating it and maintaining the temperature for a time while mixing until the composition has about the consistency of black gun powder.

5. The process of forming a molded article comprising, heating linseed oil and asphalt, adding the mixture to asbestos fiber and mixing the ingredients as they'cool,

' then raising the temperature gradually while perature sufiicient to melt the asphaltic control agent and to insure intimate mixture with the oil, then incorporating in the mixture a quantity of an inert base and allowing the mass to cool While mixing, then raising the temperature again and continuing the mixing and heating for some time till the composition is of a finely divided consistency and allowing it to cool. I

7. The process of making a molded article which includes mixing a drying oil and an asphaltic substance while hot with an inert base, then increasing the temperature and continuing the mixing action until the composition becomes a finely divided powder, then allowing it to cool, molding it under pressure While at atmospheric temperature, removing it from the mold and finally'baking it for a considerable time until hard.

8. A molded article comprising, asbestos approximately 83%, boiled linseed oil approximately 10%, asphalt approximately 7% heated and mixed asset forth, molded cold and baked and being, dense, hard, relatively non-hygroscopic high electrical resistance, low infiammability, non-oxidizing and capable of being highly polished.

9. A molded article of manufacture containing approximately 78% to'87% of inert cle,

material, from 7% to 13%,of a drying oil, and from 6%'to 9% of an asphaltic sub-' stance and having the characteristics of low inflammability, high electrical resistance and I substantially unaffected by ordinary atmospheric conditions.

10. The process of forming a molded article, which includes heating an asphaltic substance with linseed oil until the asphaltic substance is melted and mixing the two substances intimately, mixing asbestos with the melted asphaltic substance and oil'until it is in the form of a powder, drying the powder, molding the powder un er pressure to form the desired article, and afterward baking the article until it is hard and'substantially non-oxidizable. I

11. The process of forming a molded article, which includes melting a brittle grade of asphalt, and mixing it with a drying oil, then mixing the oil and melted asphalt with a greater quantity of an inert base thoroughly, then allowing the mixture to dry in the presence of air, then molding the mixture under pressure to form the'd'esired arti and then baking the article until it is hard and substantially non-oxidizable under normal atmospheric conditions.

JOHN F. OAVANAGH. 

